- Email: [email protected]
Hydrogeological, Hydrogeochemical and Isotope Geochemical Features of the Geothermal Waters in Kurşunlu, Western Anatolia, Turkey
Available online at www.sciencedirect.com
ScienceDirect Procedia Earth and Planetary Science 17 (2017) 742 – 745
15th Water-Rock Interaction International Symposium, WRI-15
Hydrogeological, hydrogeochemical and isotope geochemical features of the geothermal waters in Kurşunlu, western Anatolia, Turkey Barbaros Yıldırıma, Nevzat Özgürb,1 a Suleyman Demirel Universiy, Institute for Natural and Applied Sciences, Isparta, Turkey Sulayman Demirel University, Faculty of Engineering, Department of Geological Engineering, Isparta, Turkey
b
Abstract The geothermal waters in Kurşunlu and environs within the continental rift zone of the Gediz in the Menderes Massif can be considered as Na-HCO3 type waters. In these waters, we describe Na+K>Ca>Mg as dominant cations and HCO3>Cl>SO4 as dominant cations. The results of geochemical thermometers (quartz, Na-K and Na-K-Ca) show reservoir temperatures 120 qC in Çamurlu and 148-205 qC which correspond with calculations based on SiO2 versus enthalpy mixing model and enthalpy versus Cl mixing model of the geothermal waters in Kurşunlu and Çamurlu. The mixing ratio of geothermal waters with ground waters can be calculated due to indicators such as Cl-, B, Li, and temperatures; there is a mixing ratio of 42,5 percent geothermal waters and 57,5 percent groundwaters in Çamurlu. In Kurşunlu, we have calculated a mixing ratio of 83 percent geothermal waters and 17 percent groundwaters. © 2017 2017The TheAuthors. Authors. Published by Elsevier © Published by Elsevier B.V.B.V. This is an open access article under the CC BY-NC-ND license Peer-review under responsibility of the organizing committee of WRI-15. (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of WRI-15 Keywords: Turkey; western Anatolia; Menderes Massif; Gediz; geothermal waters; modelling
1. Introduction In the continental rift zone of the Gediz within the Menderes Massif in western Anatolia, the outlets of geothermal waters such as Urganlı, Çamur Kaplıcaları, Horsumsazdere, Alaşehir-Sarıkız, Sarıgöl-Veli Çeşmesi and Pamukkale are located (Fig. 1). The geothermal fields of Kurşunlu and Çamurlu are situated in southern part of Salihli within the continental rift zone of the Gediz. In the both thermal fields, 6 exploration, production and reinjection wells are available for further investigations. The aim of this study is (1) to update the geological * Corresponding author. E-mail address: [email protected]
1878-5220 © 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of WRI-15 doi:10.1016/j.proeps.2016.12.188
Barbaros Yıldırım and Nevzat Özgür / Procedia Earth and Planetary Science 17 (2017) 742 – 745
mapping, (2) to describe water-rock interaction by mineralogical, petrographical and geochemical methods, (3) to investigate the formation and development of the geothermal waters by hydrogeological, hydrogeochemical and isotope geochemical methods, and (4) to develop a hydrogeological model of the formation of the geothermal waters in the study area. 2. Geologic Setting The geothermal fields of Kurşunlu and Çamurlu are located in the southern part of the continental rift zone of the Gediz within the Menderes Massif and consist of Paleozoic metamorphic rocks, Miocene to Pliocene sedimentary rocks and Quaternary alluvium1,2. Precambrian to Cambrian gneisses are in the southern part of the study area and form the basement rocks which are overlined by mica schists having intercalations with phyllites, quartzites, and marbles. The quartzites and marbles show good fractures systems and can be considered as suitable reservoir rocks2,3. The mica schists have high clay contents as intercalations and play therefore an important role as impermeable basement and cap rocks. The mica schists in the basement separate from the Miocene to Pliocene sedimentary rocks by a detachment fault. The Miocen to Pliocene sedimentary rocks are conglomerates and sandstones. Within the Menderes Massif, which was uplifted due to the compressional tectonics in the Middle Miocene, the rift zones formed by extensional tectonics from Middle Miocene to recent subsequently. One of these rift zones is the Gediz in northern part of the Massif. It is represented by a great number of geothermal outlets, epithermal ore deposits and volcanic rocks from Middle Miocene to recent. Geothermal waters are related to faults which strike NW-SE and/or NE-SW diagonal to general strike of the rift zone of the Gediz. These faults are generated by compressional tectonic stresses and uplift between two extensional rift zones. In the study area, there are localities of a great number of calcalkaline basic towards acidic volcanic rocks in age ranging from Middle Miocene to recent. These volcanic rocks are of products of continental crust based on 87Sr/86Sr and 143Nd/144Nd and can be considered as heat source for heating geothermal waters in the study area.
Aegean Sea Figure 1. Geothermal fields of Kurşunlu and Çamurlu in the continental rift zone of the Gediz within the Menderes Massif (Adapted from 1,3).
3. Hydrogeology, hydrogeochemistry and isotope geochemistry 3.1 Hydrogeology In Salihli, groundwaters flow in the drainage area of the geothermal fields of Kurşunlu and Çamurlu is northwards on southern part of the rift zone of the Gediz; thereby, the geothermal water reservoir is supplied by groundwater dominantly in meteoric origin2. The distance from the watershed in Bozdağ Horst to geothermal fields of Kurşunlu and Çamurlu is about 10 km. The drainage area of the geothermal fields occupies a total area of about 150 km2. With an average annual precipitation of 652 mm and an average annual temperature of 16,6 qC, the drainage area of both geothermal fields have a semiarid climatic conditions. The Gediz is a watercourse which springs in the northern part of Kula, is supplied by a system of tributaries and leads into Aegean Sea in the northern part of İzmir. The discharge rate of the Gediz is at 20-25 m3/s in winter and 3-5 m3/s in summer. 3.2 Hydrogeochemistry In the geothermal fields of Salihli, there are five geothermal springs of Kurşunlu and Çamurlu and eight production wells2. Four of the geothermal springs are located in Kurşunlu with temperatures from 96 to 36qC. One
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of them is situated in Çamurlu. The first well located near the geothermal spring has a depth of 42.5 m, a surface temperature of 96 qC, a surface pressure of 5.5 to 6.0 bar and a flow rate of 20 l/s. The second well is located in the northern part of the first well and represents a depth of 70 m, a surface temperatures of 96 qC and a flow rate of 45 l/s. Thereby, the first 20 m depth consists of alluvium, the depth between 20,00 and 68,80 m is an alternation of mica schist and marble, and the depth between 68.80 and 70.00 m consists of marble. The third well is located in the northern part of the geothermal field of Kurşunlu and shows a depth of 117 m, a surface temperature of 96 qC, a surface pressure of 5,5 to 6,0 bar and a flow rate of 80 l/s. Drill log of this third well comprises Quaternary alluvium between 0 and 5 m, Pliocene Sedimentary rocks in a thickness from 5 to 83 m, Miocene conglomerate in depth from 83 to 92 m, Paleozoic marble in depth from 92 to 104 m and Paleozoic alternation of mica schist and marble in depth from 104 to 117 m. In the geothermal field of Salihli, the geothermal waters differ from the groundwaters and surface waters hydrogeochemically2. The geothermal waters of Salihli are of Na-K-HCO3 type water during the groundwaters show Ca-HCO3 type. In comparison to Kızıldere, the low contents of F-, SO42-, As3+ and Sb3+ and the high contents Mg2+ and Ca2+ in geothermal waters of Salihli are conspicuous distinctly. The low contents of F - can be indicated with the increasing Ca2+ offer, because the both elements in fluids can be precipitated as CaF 2. The 3H isotopes in geothermal waters of Salihli show the existence of mixing water; therefore, the components of anions and cations are diluted in comparison to Kızıldere and occur in present concentrations. The geochemical thermometer show reservoir temperatures of 147-170 qC (quartz), 140-160 qC (quartz with steam loss), 120-145 qC (chalcedony), 205-220 qC (Na-K), 195-215 qC (Na-K-Ca), 35-135 qC (Na-K-Ca-Mg), 240260 qC (Na-Li), 120-155 qC (Mg-Li) and 100-120 qC (K-Mg), thereby, the thermometers of Na-K, Na-K-Ca and quartz correspond with2 and are more suitable. In order re-examine the calculated reservoir temperatures, an enthalpy versus SiO 2 mixing model was used with respect to4 (Fig. 2). In the process, the used enthalpy values reflect surface temperatures and have been gathered from5. In this diagram, the mixing line cuts through quartz solubility curve which connects samples with meteoric groundwaters and geothermal waters at an enthalpy value at 880 kJ/kg indicating a reservoir temperature of 205 qC. This temperature estimation is based on the assumption that the steam originated by the boiling was not separated from the residual liquid phase before mixing with cold groundwaters. When the steam loss takes place before the mixing with the cold groundwaters, the enthalpy accepts the value of waters at temperatures of steam phase of 96 qC; in this process, the initial enthalpy value lies at 620 kJ/kg which corresponds to a reservoir temperature of 148 qC. A reliable calculation of temperature of geothermal water reservoir of Kurşunlu can be realized by using enthalpy versus Cl- mixing model according to6 (Figure 3). In this process. the boiling point of geothermal waters is connected with a temperature of 97 qC and Cl- contents of 72,2 mg/l. In this diagram, the boiling point of geothermal waters has an enthalpy value of 2670 kj/kg and an Cl- contents of 0 ppm. Firstly, the groundwater sample with geothermal water samples from Kurşunlu was drawn in the diagram. These are Cl- contents and measured surface temperatures. There, the mixing line affects boiling line at an enthalpy value of 500 kj/kg which corresponds a reservoir temperature of 120 qC. Finally, this leads to the reservoir temperatures of 148 to 205 qC, which corresponds to the calculated temperatures of quartz, Na-K, Na-K-Ca. The modeling indicates a pH values from 5,0 to 5,5 of the reservoirs of the geothermal waters in Kurşunlu and Çamurlu. By using indicator matters, such as Cl-, B, Li, and temperature, mixing ratio of geothermal waters and groundwaters can be calculated relatively. At Çamurlu, there is a moderate mixing ratio of 42,5 percent geothermal waters and 57,5 percent groundwaters. In comparison, 83,0 percent geothermal waters are connected with 17,0 percent groundwaters in Kurşunlu.
Figure 2. Silica versus enthalpy mixing model of 2 geothermal waters from Kurşunlu and Çamurlu .
Figure 3. Cl-versus enthalpy mixing model of geothermal waters from Kurşunlu 2 and Çamurlu .
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Barbaros Yıldırım and Nevzat Özgür / Procedia Earth and Planetary Science 17 (2017) 742 – 745
3.3 Isotope geochemistry The geothermal waters of Kurşunlu and Çamurlu can be considered meteoric water due to isotope ratio of G18O and G2H 2. The groundwaters are mixed groundwater-geothermal water systems lie along the meteoric water line(MWL). In comparison, the high temperature deep groundwater systems deviate from the MWL showing an intensively water-rock interaction under high temperature conditions. The 3H contents in investigated geothermal waters are attributed to atmospheric and anthropogenic effects. They indicate, that the geothermal waters of Kurşunlu can be considered as mixing water. The ratios of G13C in groundwaters, mixing waters and geothermal waters reveal, that the origin of CO2 can be linked to a magmatic activity by a subvolcanism in basement and to reactions with carbonate rocks. The G3He surplus in geothermal waters of Kızıldere reveal interactions of these fluids with basic to intermediate still cooling volcanic rocks of mantel and the existence of a subvolcanic intrusion2. The CO2 production in connection with carbonate rocks in reservoir dilutes 14C in geothermal waters, by which the age determination with 14C is impossible almost. 4. Conclusions In the study area of Kurşunlu together with Çamurlu, the meteoric waters in the drainage areas of the rift zones percolate at NE-SW and/or NW-SE trending fault zones and permeable clastic sediments into the reaction zone of the roof area of a magma chamber situated in a probable depth of up to 5 km where meteoric fluids are heated by the cooling magmatic melt and ascend to the surface due to their lower density caused by convection cells (Figure 2, 3). The volatile components of CO2, SO2, HCl, H2S, HB, HF, and He out of the magma reach the geothermal water reservoir where an equilibrium between altered rocks, gas components, and fluids performs. Thus, the geothermal waters ascend in the tectonical zones of weakness at the continental rift zones of the Menderes Massif in terms of hot springs, gases, and steams. These fluids are characterized by high to medium CO2, H2S and NaCl contents.
Figure 4. Simplified model of the geothermal waters of Salihli in the rift zone of the Gediz within the Menderes Massif
2,3
.
Acknowledgements This study has been supported financially by the Scientific Research Coordination Office within the Suleyman Demirel University under contract number 4139-YL1-13. References 1. Yılmazer S. Kurşunlu-Sart sıcak su kaynaklarının (Salihli) hidrojeoloji ve jeokimyasal özellikleri. Akdeniz Üniversitesi Isparta Mühendislik Fakültesi Dergisi 1988; 4: 242-266. 2. Özgür N.:Aktive und fossile Geothermalsysteme in den kontinentalen Riftzones des Menderes Massives, W-Anatolien, Türkei, Habilitationsschrift, Freie Universität Berlin, 1998, 171p. 3. Yıldırım B. Kurşunlu (Salihli, Manisa) ve yakın çevresi jeotermal sularının hidrojeolojik, hidrojeokimyasal ve izotop jeokimyasal özellikleri. M. Sc. thesis, Suleyman Demirel University 2016, 82 p. 4. Fournier R. O. Chemical geothermometers and mixing models for geothermal systems. Geothermics 1977; 5: 41-50. 5. Henley R.W, Truesdell, AH, Barton, PB, Whitney JA. Fluid-mineral equilibria in hydrothermal systems. Econ. Geol. Rev. 1984; 1: 267 p. 6. Truesdell AH, Fournier RO. Calculations of deep temperatures in geothermal systems from the chemistry of boiling spring waters of mixed origin. Proc. 2nd UN Symp. on the Development and Use of geothermal Resources 1975; 1:833-844.
ScienceDirect Procedia Earth and Planetary Science 17 (2017) 742 – 745
15th Water-Rock Interaction International Symposium, WRI-15
Hydrogeological, hydrogeochemical and isotope geochemical features of the geothermal waters in Kurşunlu, western Anatolia, Turkey Barbaros Yıldırıma, Nevzat Özgürb,1 a Suleyman Demirel Universiy, Institute for Natural and Applied Sciences, Isparta, Turkey Sulayman Demirel University, Faculty of Engineering, Department of Geological Engineering, Isparta, Turkey
b
Abstract The geothermal waters in Kurşunlu and environs within the continental rift zone of the Gediz in the Menderes Massif can be considered as Na-HCO3 type waters. In these waters, we describe Na+K>Ca>Mg as dominant cations and HCO3>Cl>SO4 as dominant cations. The results of geochemical thermometers (quartz, Na-K and Na-K-Ca) show reservoir temperatures 120 qC in Çamurlu and 148-205 qC which correspond with calculations based on SiO2 versus enthalpy mixing model and enthalpy versus Cl mixing model of the geothermal waters in Kurşunlu and Çamurlu. The mixing ratio of geothermal waters with ground waters can be calculated due to indicators such as Cl-, B, Li, and temperatures; there is a mixing ratio of 42,5 percent geothermal waters and 57,5 percent groundwaters in Çamurlu. In Kurşunlu, we have calculated a mixing ratio of 83 percent geothermal waters and 17 percent groundwaters. © 2017 2017The TheAuthors. Authors. Published by Elsevier © Published by Elsevier B.V.B.V. This is an open access article under the CC BY-NC-ND license Peer-review under responsibility of the organizing committee of WRI-15. (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of WRI-15 Keywords: Turkey; western Anatolia; Menderes Massif; Gediz; geothermal waters; modelling
1. Introduction In the continental rift zone of the Gediz within the Menderes Massif in western Anatolia, the outlets of geothermal waters such as Urganlı, Çamur Kaplıcaları, Horsumsazdere, Alaşehir-Sarıkız, Sarıgöl-Veli Çeşmesi and Pamukkale are located (Fig. 1). The geothermal fields of Kurşunlu and Çamurlu are situated in southern part of Salihli within the continental rift zone of the Gediz. In the both thermal fields, 6 exploration, production and reinjection wells are available for further investigations. The aim of this study is (1) to update the geological * Corresponding author. E-mail address: [email protected]
1878-5220 © 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of WRI-15 doi:10.1016/j.proeps.2016.12.188
Barbaros Yıldırım and Nevzat Özgür / Procedia Earth and Planetary Science 17 (2017) 742 – 745
mapping, (2) to describe water-rock interaction by mineralogical, petrographical and geochemical methods, (3) to investigate the formation and development of the geothermal waters by hydrogeological, hydrogeochemical and isotope geochemical methods, and (4) to develop a hydrogeological model of the formation of the geothermal waters in the study area. 2. Geologic Setting The geothermal fields of Kurşunlu and Çamurlu are located in the southern part of the continental rift zone of the Gediz within the Menderes Massif and consist of Paleozoic metamorphic rocks, Miocene to Pliocene sedimentary rocks and Quaternary alluvium1,2. Precambrian to Cambrian gneisses are in the southern part of the study area and form the basement rocks which are overlined by mica schists having intercalations with phyllites, quartzites, and marbles. The quartzites and marbles show good fractures systems and can be considered as suitable reservoir rocks2,3. The mica schists have high clay contents as intercalations and play therefore an important role as impermeable basement and cap rocks. The mica schists in the basement separate from the Miocene to Pliocene sedimentary rocks by a detachment fault. The Miocen to Pliocene sedimentary rocks are conglomerates and sandstones. Within the Menderes Massif, which was uplifted due to the compressional tectonics in the Middle Miocene, the rift zones formed by extensional tectonics from Middle Miocene to recent subsequently. One of these rift zones is the Gediz in northern part of the Massif. It is represented by a great number of geothermal outlets, epithermal ore deposits and volcanic rocks from Middle Miocene to recent. Geothermal waters are related to faults which strike NW-SE and/or NE-SW diagonal to general strike of the rift zone of the Gediz. These faults are generated by compressional tectonic stresses and uplift between two extensional rift zones. In the study area, there are localities of a great number of calcalkaline basic towards acidic volcanic rocks in age ranging from Middle Miocene to recent. These volcanic rocks are of products of continental crust based on 87Sr/86Sr and 143Nd/144Nd and can be considered as heat source for heating geothermal waters in the study area.
Aegean Sea Figure 1. Geothermal fields of Kurşunlu and Çamurlu in the continental rift zone of the Gediz within the Menderes Massif (Adapted from 1,3).
3. Hydrogeology, hydrogeochemistry and isotope geochemistry 3.1 Hydrogeology In Salihli, groundwaters flow in the drainage area of the geothermal fields of Kurşunlu and Çamurlu is northwards on southern part of the rift zone of the Gediz; thereby, the geothermal water reservoir is supplied by groundwater dominantly in meteoric origin2. The distance from the watershed in Bozdağ Horst to geothermal fields of Kurşunlu and Çamurlu is about 10 km. The drainage area of the geothermal fields occupies a total area of about 150 km2. With an average annual precipitation of 652 mm and an average annual temperature of 16,6 qC, the drainage area of both geothermal fields have a semiarid climatic conditions. The Gediz is a watercourse which springs in the northern part of Kula, is supplied by a system of tributaries and leads into Aegean Sea in the northern part of İzmir. The discharge rate of the Gediz is at 20-25 m3/s in winter and 3-5 m3/s in summer. 3.2 Hydrogeochemistry In the geothermal fields of Salihli, there are five geothermal springs of Kurşunlu and Çamurlu and eight production wells2. Four of the geothermal springs are located in Kurşunlu with temperatures from 96 to 36qC. One
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of them is situated in Çamurlu. The first well located near the geothermal spring has a depth of 42.5 m, a surface temperature of 96 qC, a surface pressure of 5.5 to 6.0 bar and a flow rate of 20 l/s. The second well is located in the northern part of the first well and represents a depth of 70 m, a surface temperatures of 96 qC and a flow rate of 45 l/s. Thereby, the first 20 m depth consists of alluvium, the depth between 20,00 and 68,80 m is an alternation of mica schist and marble, and the depth between 68.80 and 70.00 m consists of marble. The third well is located in the northern part of the geothermal field of Kurşunlu and shows a depth of 117 m, a surface temperature of 96 qC, a surface pressure of 5,5 to 6,0 bar and a flow rate of 80 l/s. Drill log of this third well comprises Quaternary alluvium between 0 and 5 m, Pliocene Sedimentary rocks in a thickness from 5 to 83 m, Miocene conglomerate in depth from 83 to 92 m, Paleozoic marble in depth from 92 to 104 m and Paleozoic alternation of mica schist and marble in depth from 104 to 117 m. In the geothermal field of Salihli, the geothermal waters differ from the groundwaters and surface waters hydrogeochemically2. The geothermal waters of Salihli are of Na-K-HCO3 type water during the groundwaters show Ca-HCO3 type. In comparison to Kızıldere, the low contents of F-, SO42-, As3+ and Sb3+ and the high contents Mg2+ and Ca2+ in geothermal waters of Salihli are conspicuous distinctly. The low contents of F - can be indicated with the increasing Ca2+ offer, because the both elements in fluids can be precipitated as CaF 2. The 3H isotopes in geothermal waters of Salihli show the existence of mixing water; therefore, the components of anions and cations are diluted in comparison to Kızıldere and occur in present concentrations. The geochemical thermometer show reservoir temperatures of 147-170 qC (quartz), 140-160 qC (quartz with steam loss), 120-145 qC (chalcedony), 205-220 qC (Na-K), 195-215 qC (Na-K-Ca), 35-135 qC (Na-K-Ca-Mg), 240260 qC (Na-Li), 120-155 qC (Mg-Li) and 100-120 qC (K-Mg), thereby, the thermometers of Na-K, Na-K-Ca and quartz correspond with2 and are more suitable. In order re-examine the calculated reservoir temperatures, an enthalpy versus SiO 2 mixing model was used with respect to4 (Fig. 2). In the process, the used enthalpy values reflect surface temperatures and have been gathered from5. In this diagram, the mixing line cuts through quartz solubility curve which connects samples with meteoric groundwaters and geothermal waters at an enthalpy value at 880 kJ/kg indicating a reservoir temperature of 205 qC. This temperature estimation is based on the assumption that the steam originated by the boiling was not separated from the residual liquid phase before mixing with cold groundwaters. When the steam loss takes place before the mixing with the cold groundwaters, the enthalpy accepts the value of waters at temperatures of steam phase of 96 qC; in this process, the initial enthalpy value lies at 620 kJ/kg which corresponds to a reservoir temperature of 148 qC. A reliable calculation of temperature of geothermal water reservoir of Kurşunlu can be realized by using enthalpy versus Cl- mixing model according to6 (Figure 3). In this process. the boiling point of geothermal waters is connected with a temperature of 97 qC and Cl- contents of 72,2 mg/l. In this diagram, the boiling point of geothermal waters has an enthalpy value of 2670 kj/kg and an Cl- contents of 0 ppm. Firstly, the groundwater sample with geothermal water samples from Kurşunlu was drawn in the diagram. These are Cl- contents and measured surface temperatures. There, the mixing line affects boiling line at an enthalpy value of 500 kj/kg which corresponds a reservoir temperature of 120 qC. Finally, this leads to the reservoir temperatures of 148 to 205 qC, which corresponds to the calculated temperatures of quartz, Na-K, Na-K-Ca. The modeling indicates a pH values from 5,0 to 5,5 of the reservoirs of the geothermal waters in Kurşunlu and Çamurlu. By using indicator matters, such as Cl-, B, Li, and temperature, mixing ratio of geothermal waters and groundwaters can be calculated relatively. At Çamurlu, there is a moderate mixing ratio of 42,5 percent geothermal waters and 57,5 percent groundwaters. In comparison, 83,0 percent geothermal waters are connected with 17,0 percent groundwaters in Kurşunlu.
Figure 2. Silica versus enthalpy mixing model of 2 geothermal waters from Kurşunlu and Çamurlu .
Figure 3. Cl-versus enthalpy mixing model of geothermal waters from Kurşunlu 2 and Çamurlu .
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Barbaros Yıldırım and Nevzat Özgür / Procedia Earth and Planetary Science 17 (2017) 742 – 745
3.3 Isotope geochemistry The geothermal waters of Kurşunlu and Çamurlu can be considered meteoric water due to isotope ratio of G18O and G2H 2. The groundwaters are mixed groundwater-geothermal water systems lie along the meteoric water line(MWL). In comparison, the high temperature deep groundwater systems deviate from the MWL showing an intensively water-rock interaction under high temperature conditions. The 3H contents in investigated geothermal waters are attributed to atmospheric and anthropogenic effects. They indicate, that the geothermal waters of Kurşunlu can be considered as mixing water. The ratios of G13C in groundwaters, mixing waters and geothermal waters reveal, that the origin of CO2 can be linked to a magmatic activity by a subvolcanism in basement and to reactions with carbonate rocks. The G3He surplus in geothermal waters of Kızıldere reveal interactions of these fluids with basic to intermediate still cooling volcanic rocks of mantel and the existence of a subvolcanic intrusion2. The CO2 production in connection with carbonate rocks in reservoir dilutes 14C in geothermal waters, by which the age determination with 14C is impossible almost. 4. Conclusions In the study area of Kurşunlu together with Çamurlu, the meteoric waters in the drainage areas of the rift zones percolate at NE-SW and/or NW-SE trending fault zones and permeable clastic sediments into the reaction zone of the roof area of a magma chamber situated in a probable depth of up to 5 km where meteoric fluids are heated by the cooling magmatic melt and ascend to the surface due to their lower density caused by convection cells (Figure 2, 3). The volatile components of CO2, SO2, HCl, H2S, HB, HF, and He out of the magma reach the geothermal water reservoir where an equilibrium between altered rocks, gas components, and fluids performs. Thus, the geothermal waters ascend in the tectonical zones of weakness at the continental rift zones of the Menderes Massif in terms of hot springs, gases, and steams. These fluids are characterized by high to medium CO2, H2S and NaCl contents.
Figure 4. Simplified model of the geothermal waters of Salihli in the rift zone of the Gediz within the Menderes Massif
2,3
.
Acknowledgements This study has been supported financially by the Scientific Research Coordination Office within the Suleyman Demirel University under contract number 4139-YL1-13. References 1. Yılmazer S. Kurşunlu-Sart sıcak su kaynaklarının (Salihli) hidrojeoloji ve jeokimyasal özellikleri. Akdeniz Üniversitesi Isparta Mühendislik Fakültesi Dergisi 1988; 4: 242-266. 2. Özgür N.:Aktive und fossile Geothermalsysteme in den kontinentalen Riftzones des Menderes Massives, W-Anatolien, Türkei, Habilitationsschrift, Freie Universität Berlin, 1998, 171p. 3. Yıldırım B. Kurşunlu (Salihli, Manisa) ve yakın çevresi jeotermal sularının hidrojeolojik, hidrojeokimyasal ve izotop jeokimyasal özellikleri. M. Sc. thesis, Suleyman Demirel University 2016, 82 p. 4. Fournier R. O. Chemical geothermometers and mixing models for geothermal systems. Geothermics 1977; 5: 41-50. 5. Henley R.W, Truesdell, AH, Barton, PB, Whitney JA. Fluid-mineral equilibria in hydrothermal systems. Econ. Geol. Rev. 1984; 1: 267 p. 6. Truesdell AH, Fournier RO. Calculations of deep temperatures in geothermal systems from the chemistry of boiling spring waters of mixed origin. Proc. 2nd UN Symp. on the Development and Use of geothermal Resources 1975; 1:833-844.